It's easy. Search and you'll find info.
Here is what I used:
CBA/Tatone Tailwheel Assembly .40 size:
http://www2.towerhobbies.com/cgi-bin...?&I=LXA386&P=7
Great Planes "Large 60" size dural main gear:
http://www2.towerhobbies.com/cgi-bin...&I=LXJ924&P=ML
The "Large 60" size GP gear are not too large. They are just right. They wheel spacing is about
14 inches - whichs matches the original.
Dubro make some main gear that should work also:
http://www2.towerhobbies.com/cgi-bin...&I=LXNM65&P=ML
Put an extra sheet of 1/8 ply inside the fuse the bolt the gear onto. Some 1/2 tri-stock bracing around that area of the fuse would not hurt. The wheels should line up, approximately, with the leading edge of the wing.
Run an extra push rod from the rudder servo down to the tail wheel's tiller arm. Or run pull cables.